For many years there has been a raging battle concerning the wisdom of high altitude training for the low altitude athlete. Advocates of high altitude training cited the numerous studies that all show that the number of red blood cells increased and the aerobic capacity increased after some extended stay at altitude, i.e., after acclimatization. Opponents to altitude training for the sea level athletes, while acknowledging the increase in the hemoglobin in these subjects, cited well-documented evidence that since the performance of the athlete was so poor at altitude, a maximum training regime was never possible to initiate. Thus, maximum training could never occur. One clear solution that would answer both objections would simply have the athlete live at altitude but train at sea level. In this way he or she would obtain the maximum benefit from both the high altitude and low altitude physiology. Since de-acclimatization takes several weeks, there is virtually no effect if the athlete descends quickly to sea level for training and then reascends for the rest of his or her nontraining time. This descent could be done either by physically transporting the person to or near sea level or accomplishing the same effect via a hyperbaric chamber.
Recently there was a report from Salt Lake City (Levine, B. D. et al. (Apr 1991) Medicine and Science in Sports and Exercise 23(4), Suppl. 145; and Levine, B. D. and Houston, C., "Benefits of training at high altitude: myth or reality," The Seventh International Hypoxia Symposium) clearly demonstrating that athletes living at Snowbird, Utah (8,000 ft.), but training at Salt Lake City, Utah (4,500 ft.), were significantly more fit than the control group that both lived and trained at Salt Lake City.
Presently the Olympic Training Center (OTC) in Colorado Springs is repeating this study and taking it further (May, C. (November 1991), "the Town That Can't Sit Still," New York Times Magazine, p. 58). The OTC is comparing and contrasting four situations: 1. Live high and train high; 2. Live low and train low; 3. Live low and train high; and 4. Live high and train low. These studies all deal with determining the fitness level of athletes such as runners and bicyclists, but there have also been several reports that high altitude climbers that spent time in a hypobaric chamber (altitude chamber) previous to climbing a mountain at altitude were better acclimatized when starting the climb because of the time spent in the hypobaric chamber (Richalet, J. P., "Effects of Acute and Chronic Hypoxia in Human Erthropoeitin Control at Rest and Exercise," Abstract 90, The Seventh International Hypoxia Symposium; Escoffier, E. (1990), "Everest Attempt and Acclimatization Experiment," The American Alpine Journal, pp. 303-304; and Endo, Y. (1989), "High Mountain Research Center, Nagoya, Japan," The American Alpine Journal, p. 266). These two lines of evidence both show that time spent at altitude results in an increase in the number of red blood cells which is reflected in the acclimatization in the mountain climbers as it also is in athletes.
Previously-known hypobaric chambers have been large, heavy structures with walls made of structurally rigid materials such as concrete or metal which can simulate altitudes of 50,000 to several hundred-thousand feet and are used for such purposes as pilot training.
Portable hyperbaric chambers are known. For example, U.S. Pat. No. 4,974,829 to Gamow et al. discloses a spherical-shaped hyperbaric chamber useful for physical conditioning for athletes, and a cylindrically-shaped hyperbaric mountain bag in which mountain climbers suffering from altitude sickness can be placed in a higher pressure equivalent to descent to a lower altitude for alleviation of their symptoms.
U.S. Pat. No. 5,063,924 to Galvan et al. discloses a portable enclosed chamber for providing a controlled atmosphere which may be pressurized to aid individuals in breathing in toxic atmospheres.
U.S. Pat. No. 4,106,504 to York discloses a portable recompression chamber capable of being pressurized to a desired ocean depth pressure.
U.S. Pat. No. 3,729,002 to Miller discloses a portable, collapsible recompression chamber for achieving ocean depth pressures.
U.S. Pat. No. 2,401,230 to Colley discloses a portable hyperbaric chamber capable of pressurization for use during air flight at high altitudes.
U.S. Pat. No. 1,294,188 to Stelzner discloses a portable, collapsible decompression chamber which can be pressurized to ocean depth pressures.
U.S. Pat. No. 4,621,621 to Marsalis discloses a portable hypobaric device which is a respirator breathing jacket. The jacket assembly has a screen-like grid curved to fit over the torso of the user in spaced apart position from the torso, with an airtight poncho-like jacket positioned over the grid. A vacuum pump and valve assembly allows air to be alternately exhausted from and communicated into the jacket to cause the user to inhale and exhale.
Oxygen monitoring devices are also known to the art, e.g., as described in U.S. Pat. Nos. 4,914,424 to Hirao et al.; 4,462,246 to Advani et al.; and 4,189,725 to Rowland et al.
None of the foregoing patents disclose a lightweight, portable hypobaric chamber designed for only one or two reclining persons.